Jacoby notes that throughout history civil wars have been more barbaric than wars against outsiders. Confounding all reason, neighbors and kinsmen turn on one another in such ways that they do not when it comes to interstate conflicts.

“There was death in every shape and form,” writes Thucydides. “People went to every extreme and beyond it. There were fathers who killed their sons; men were dragged from the temples and butchered on the very altars.” Families turned on families. “Blood ties became more foreign than factional ones.” Loyalty to the faction overrode loyalty to family members who became the enemy.

For Thucydides the “passions of civil war” leave no room for compromise. The impulse of revenge undermines reconciliation. “Personal ambition” and “violent fanaticism” drive the conflict. “The victims [members of the anti-Athenian faction] were accused of conspiring to overthrow democracy, but in fact men were often killed on grounds of personal hatred or else by their debtors because of the money they owed.” The Venetian ambassador’s report on the St. Bartholomew’s Day Massacre two thousand years later used almost the same words. The crowd had no mercy, he wrote in 1572. “If one man hated another because of some argument or lawsuit, all he had to say was ‘This man is Huguenot’ and he was immediately killed. (That happened to many Catholics.)” Such is civil dissension across the millennia. Hatreds and grudges often overwhelm principles and politics (p. 42).

Having seen doctrinal controversies and church splits up close, I’m amazed by how many of them begin with petty grievances, jealousies, or long-held grudges against others.

I’m also struck by how the tribalism of contemporary American evangelicalism has led to the employment of such vicious rhetoric to speak of fellow Christians. Confessing evangelical people will say things on blogs and in print about other Christians that I suspect they would not say about others in public.

One other passage in Jacoby struck me. He uses psychoanalytic descriptive tools here and there to great effect, as he does in speaking of the Balkan conflicts leading up to the first world war.

The two Balkan wars might be considered a short course in the dialectic of violence. The attack on the outsider makes way for the attack on the insider. To use psychoanalytic logic, first the father is overthrown, and then the brothers turn on one another (p. 38).

Many others have noted how it is that the fundamentalist-liberal controversies in the early part of the last century fostered an ethos of conflict and contentiousness. One of the banner Bible texts in those days was Jude 3—“always contending for the faith once delivered unto the saints.”

The culture of conflict took such hold, however, that fundamentalists and later evangelicals never cultivated alternative ways of imagining Christian existence. “Godliness” meant fighting. People who expressed a desire to defend the faith and fight against heretics were promoted, sent off to seminary, and installed in pulpits.

The problem, however, was that having separated from liberals, there was no one left to fight but one another. The smallest differences in doctrinal articulation or worship style became the theaters of never-ending conflict. The roots of the tribalism of which Mickey Maudlin speaks go back at least a century and even deeper into the history of human behavior.

Takashi Kojima

I guess the roots of tribalistic theological disputes are many and complex. It’s undoubtedly true that what you see and describe in the theological rivalries as barbaric is not limited in the U.S. I see a similar phenomenon in my country, too. But, the in-fighting in the U.S., my knowledge is very limited though, is particularly ferocious.
I don’t know but it looks it’s a legacy of modernism, Those who engage in theological battles are so en-armored with their vision of THE TRUTH but become psychologically so insecure when challenged. They get agitated and easily drawn to a serious battle mode. That’s because they think it’s the only way to defend the truth. Yes, they tend to monopolize and privatize “truth.” They don’t want to hold a PUBLIC debate with appropriate virtues, such as dialectical, dialogical manners in the exchange of views. In that sense, your characterization as barbaric is so apt.